Methods for operating an autonomous vehicle and autonomous vehicle

Abstract

The invention relates to a method for operating an autonomous vehicle (10), wherein the autonomous vehicle (10) is maneuvered on a roadway. In a method that maximizes the comfort of the driving experience for a passenger, it is provided that it is determined whether the autonomous vehicle (10) is on a multi-lane roadway (12), wherein, when cornering, a lane change is carried out such that, if the autonomous vehicle (10) is on a multi-lane roadway (12), the lateral acceleration during cornering is below a predetermined lateral acceleration limit.

Description

[0001] The invention relates to a method for operating an autonomous vehicle, wherein the vehicle is maneuvered on a roadway, and it is determined whether the vehicle is on a multi-lane roadway.

[0002] In addition, the invention relates to an autonomous vehicle with at least one evaluation unit and with at least one control unit.

[0003] In autonomous vehicles, where the driver is relieved of the driving task, travel time can be used for previously unavailable secondary activities. For example, office work could be performed, allowing travel time during working hours to be used efficiently. To enable vehicle maneuvering, lane-keeping systems for vehicles, particularly motor vehicles, are known in the prior art. These systems react when the vehicle threatens to leave its lane. The vehicle's trajectory is corrected when a tendency to leave the lane is detected. Steering is initiated, and the vehicle follows the prescribed lane.

[0004] Various methods for operating an autonomous vehicle are known from the prior art. US 2021 / 0165409A1, for example, discloses a vehicle control system that uses a control function to transition the vehicle's current state to a target state. The control function is probabilistic in order to output a parametric probability distribution over the target state, defined by a first moment and at least one higher-order moment.The control unit subjects the current state to at least a subset of control functions consistent with the next driving decision in order to generate a subset of parametric probability distributions over the target state, combines the subset of parametric probability distributions to generate a joint parametric probability distribution of the target state, and determines the control command based on the first moment and at least one higher-order moment of the joint parametric probability distribution of the target state.

[0005] US Patent 2020 / 0122721A1 discloses a method for determining a smooth reference line for the navigation of an autonomous vehicle in a manner similar to human driving. A high-density map is used to generate a centerline for a lane. Using the centerline, a number of sample points are generated, related to the curvature of the centerline. At each sample point, fit points are generated, some on both sides of the centerline at each sample point. The potential fit points at a sample point include the fit points and the sample point itself. A path with the lowest cost through each of the candidate points at each sample point is determined. The path cost is based on the approach and departure angles through a candidate point and the candidate point's distance from the centerline.

[0006] US Patent 2020 / 0142417A1 discloses techniques for generating trajectories and traversable areas for vehicle navigation in an environment. These techniques may involve receiving a reference trajectory, which provides an initial trajectory for a vehicle, such as an autonomous vehicle, to traverse the environment. A point density can be determined for various segments of the reference trajectory. In some cases, the point density may be based, at least in part, on costs associated with a curvature value assigned to the reference trajectory or on costs associated with a distance between the reference trajectory and an obstacle in the environment.

[0007] In such journeys, in addition to reduced costs, passenger comfort plays a significant role. Especially when cornering, a passenger may experience a rough ride if they are subjected to centrifugal forces acting on them, either inwards or outwards.

[0008] The invention is based on the objective of providing a method for operating an autonomous vehicle and an autonomous vehicle in which the comfort of the driving experience for a passenger is maximized.

[0009] The aforementioned problem is initially solved in the present invention by the features of claim 1 in that, when cornering, a lane change is carried out in such a way that the lateral acceleration during cornering remains below a predetermined lateral acceleration limit when the vehicle is on a multi-lane roadway.

[0010] The roadway is the portion of the route traveled by a vehicle or autonomous vehicle. The route can be determined using navigation data. The roadway can consist of various surfaces. Preferably, the roadway is a paved, especially asphalt, road. However, driving on unpaved roads, such as forest tracks or gravel roads, is also conceivable.

[0011] Such roads can be multi-lane. Multi-lane means that there is more than one lane. Preferably, a multi-lane road is one with several lanes in the same direction of travel. However, it is also conceivable that the opposite lane is used as an additional lane if legal regulations permit changing lanes onto the opposite lane.

[0012] Determining whether a vehicle is on a multi-lane road can be done using various sensors, such as cameras, lidar, radar, ultrasound, or similar suitable sensors. However, the use of navigation data and / or swarm data is also conceivable.

[0013] A lane change occurs when driving from one lane to another. Ideally, there are lane markings that clearly indicate the lanes. In this case, a lane change is defined as crossing a lane marking.

[0014] Lateral acceleration refers to acceleration in the y-direction of the vehicle's fixed coordinate system, or acceleration in the side direction of the vehicle. This acceleration causes centrifugal forces to act on a passenger, resulting in a force acting on them inside the vehicle either outwards, towards the vehicle door, or inwards, for example towards a center console.

[0015] This lateral acceleration is proportional to the force acting on the passenger. Therefore, a lateral acceleration limit is set below which the passenger can enjoy a comfortable driving experience, or below which the force acting on the passenger is so great that it is not perceived as disturbing or even noticeable.

[0016] Further preferred embodiments of the invention result from the other features mentioned in the dependent claims.

[0017] In a first embodiment of the method according to the invention, a lane change during cornering is performed in such a way that the curvature of the curve being driven remains below a predetermined curvature limit. Lateral acceleration depends proportionally on the curvature of the curve or the radius of the curve. The tighter the curve, the greater the lateral acceleration at the same speed. Therefore, if the curvature is minimized during cornering, i.e., if the curve being driven is "smoothed out," the lateral acceleration is also simultaneously minimized, thereby increasing the passenger's comfort during the driving experience.

[0018] In a further embodiment of the method according to the invention, it is provided that multiple lane changes occur when navigating a series of curves. A series of curves could, for example, involve a change from a left-hand curve to a right-hand curve, or vice versa. Other combinations are also conceivable. In this case, a series of curves also includes a curve that may contain a short straight section before the next curve is initiated. Multiple lane changes are therefore necessary to "smooth out" the curve and allow the autonomous vehicle to travel in a straight line for as long as possible without strictly following the curve's contour.

[0019] Additionally or alternatively, a further embodiment of the invention provides that an initial lane change to the outermost lane occurs before cornering. This minimizes lateral acceleration and the curvature of the curve. By approaching the curve in the outermost lane, the autonomous vehicle can drive in a straight line into the curve up to a certain point. In doing so, the autonomous vehicle crosses several lanes that would otherwise follow the curve's contour.

[0020] In a particularly preferred embodiment of the method according to the invention, an evaluation unit calculates an optimal trajectory for an upcoming curve, and the evaluation unit transmits a command, depending on the optimal trajectory, to at least one control unit, which then regulates or controls the curve. The optimal trajectory is based on the lateral acceleration limit. The trajectory would therefore be optimal if the lateral acceleration limit is not exceeded throughout the entire curve. The data used to determine the optimal trajectory can be derived from the system's own sensor data, for example, camera data, lidar, radar, and / or ultrasonic sensors. It is also conceivable to use navigation data and / or swarm data from other vehicles that have already driven this section of the road.By using swarm data and evaluating the resulting lateral accelerations, the optimal trajectory for the route segment can be determined iteratively.

[0021] In a further embodiment of the method according to the invention, it is advantageous to combine several lanes into one when calculating the optimal trajectory. In this way, the combined width of all lanes can be used for the calculation, thereby simplifying the calculation of the optimal trajectory and, in particular, a trajectory with the minimum lateral acceleration.

[0022] In a further embodiment of the method according to the invention, the optimal trajectory is determined taking into account other road users on a preceding lane. To ensure safety when changing lanes, the optimal trajectory is determined considering other road users. These other road users can be vehicles ahead, but also pedestrians or vulnerable road users who are on the lane or crossing it. It is also conceivable to consider whether another road user might potentially cross the lane while continuing along a trajectory.

[0023] Furthermore, in a further embodiment of the method according to the invention, the optimal trajectory is determined taking local legislation into account. In this way, it can be considered that, for example, a lane change must not occur under any circumstances in a specific section of the route because local legislation so stipulates, even if it would otherwise be technically possible to perform a lane change.

[0024] In a further embodiment of the method according to the invention, it is also provided that the autonomous vehicle activates its turn signal when crossing a lane. The automatic activation of the turn signal, ideally within a certain timeframe before the lane change, helps following traffic to determine how the autonomous vehicle will drive. Since multiple lane changes are generally unnecessary, drivers of vehicles where the driving task is left to the human driver could be confused. Such confusion can be avoided by indicating the impending lane change in advance.

[0025] The aforementioned problem is also solved by an autonomous vehicle with at least one evaluation unit and at least one control unit. The evaluation unit is configured and designed to carry out a method according to the invention. The preceding descriptions concerning the method according to the invention also apply accordingly to the autonomous vehicle according to the invention.

[0026] Electronic or electrical devices and / or other relevant devices or components according to the embodiments of the present invention described herein can be implemented using any suitable hardware, firmware (e.g., an application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of these devices can be placed on an integrated circuit (IC) or on separate IC chips. Furthermore, the various components of these devices can be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or on a single substrate.Furthermore, the various components of these devices can be a process or thread running on one or more processors in one or more computer devices, executing computer program instructions, and interacting with other system components to perform the various functions described here. The computer program instructions are stored in memory, which can be implemented in a computer device using standard memory, such as main memory (RAM). The computer program instructions can also be stored on other non-transferable, computer-readable media, such as a CD-ROM, a flash drive, or similar devices.A competent person should also recognize that the functionality of different computer devices can be combined or integrated into a single computer device, or that the functionality of a particular computer device can be distributed among one or more other computer devices, without deviating from the scope of application of the exemplary embodiments of the present invention.

[0027] Unless otherwise stated in individual cases, the various embodiments of the invention mentioned in this application can be advantageously combined with one another.

[0028] The invention is explained below using exemplary embodiments with reference to the accompanying drawings. These show: Fig. 1 A schematic representation of an embodiment of the implementation of a method for operating an autonomous vehicle to improve passenger comfort and Fig. Two different steps of an exemplary embodiment of a method for operating an autonomous vehicle in a block diagram.

[0029] Fig. Figure 1 shows a method for operating an autonomous vehicle 10. The autonomous vehicle 10 is maneuvered on a roadway. It is determined whether the autonomous vehicle 10 is on a multi-lane roadway 12. When cornering, a lane change is performed in such a way that the lateral acceleration during the cornering maneuver remains below a predetermined lateral acceleration limit. Additionally, the lane change during cornering is performed in such a way that the curvature of the curve 14 remains below a predetermined curvature limit. The lateral acceleration depends proportionally on the curvature of the curve. The tighter the curve, the greater the lateral acceleration at the same speed. Therefore, if the curvature is minimized during cornering, i.e., if the curve 14 is "smoothed out," the lateral acceleration is also minimized, thus improving the passenger's comfort during the ride.

[0030] It is intended that several lane changes occur during a series of curves. In this embodiment, the curve combination is a change from a left-hand curve to a right-hand curve. Due to the multiple lane changes, the autonomous vehicle 10 needs to steer as little as possible and can navigate curve 14 with minimal lateral acceleration. Logically, the contour 16 of curve 14 is not followed exactly. The path 18 traveled by the autonomous vehicle 10 then looks like this: Fig. 1 shown.

[0031] Furthermore, it is planned that an initial lane change to the outermost lane 20 will occur before entering a curve. This further minimizes the lateral acceleration, or rather the curvature of the curve 14 to be negotiated. By approaching curve 14 in the outermost lane 20, the autonomous vehicle 10 can drive into the curve in a straight line up to a certain point. In doing so, the autonomous vehicle 10 crosses several lanes that would otherwise follow the contour of the curve.

[0032] Fig.Figure 2 shows various steps of the procedure for operating the autonomous vehicle 10. In step 100, an evaluation unit 22 of the autonomous vehicle 10 calculates an optimal trajectory for an upcoming curve. In step 102, the evaluation unit 22 transmits a command, based on the optimal trajectory, to several control units 24 of the autonomous vehicle 10, whereby the curve is regulated or controlled by the control units 24. The optimal trajectory is based on the lateral acceleration limit. The trajectory is therefore optimal if the lateral acceleration limit is not exceeded throughout the entire curve.

[0033] The process for calculating the optimal trajectory is further subdivided into sub-steps. Step 104 involves first collecting and evaluating data to serve as the basis for calculating the optimal trajectory. This data can be derived from the system's own sensor data, such as camera, lidar, radar, and / or ultrasonic sensors. Alternatively, navigation data and / or swarm data from other vehicles that have already traveled this section of the route can be used. By utilizing swarm data and evaluating the resulting lateral accelerations, the optimal trajectory for this section can be determined iteratively.

[0034] In step 106, the actual calculation begins, whereby several detected lanes are combined into one when calculating the optimal trajectory. This allows the combined width of all lanes to be used for the calculation, resulting in a simplified calculation of the optimal trajectory and, in particular, a trajectory with the minimum lateral acceleration.

[0035] In step 108, a further iteration is performed to calculate the trajectory, determining the optimal trajectory taking into account other road users 26 located on a preceding lane. To ensure safety when changing lanes, the optimal trajectory is determined considering other road users. Other road users 26 can be vehicles ahead, but also pedestrians or vulnerable road users who are on the lane or crossing the lane 18. It is also conceivable to consider whether another road user 26 might potentially cross the lane 18 if they continue along a trajectory.

[0036] In step 110, the optimal trajectory is determined in a further iteration, taking local legislation into account. This allows for consideration of situations where, for example, a lane change is absolutely prohibited in a specific section of the route due to local regulations, even if a lane change would otherwise be technically feasible. Reference symbol list 10 autonomous vehicles 12 multi-lane roadway 14 Curve 16 contour 18 Route 20 outermost lane 22 Evaluation unit 24 Control unit 26 other road users QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2021 / 0 165 409 A1

[0004] US 2020 / 0 122 721 A1

[0005] US 2020 / 0 142 417 A1

[0006]

Claims

[1] Method for operating an autonomous vehicle (10), wherein the autonomous vehicle (10) is maneuvered on a roadway, determining whether the autonomous vehicle (10) is on a multi-lane roadway (12), where, when cornering, a lane change is carried out in such a way as to ensure that the autonomous vehicle (10) is on a multi-lane roadway (12), that the lateral acceleration during cornering is below a predetermined lateral acceleration limit. [2] Method according to claim 1, wherein a lane change during a curve is carried out such that the curvature of the curve driven (14) is below a predetermined curvature limit value. [3] Method according to claim 1 or 2, wherein multiple lane changes are performed during a combination of curves driven. [4] Method according to one of claims 1 to 3, wherein an initial lane change to the outermost lane (20) is performed before driving around a curve. [5] Method according to one of claims 1 to 4, wherein an evaluation device (22) calculates an optimal trajectory for an upcoming curve and wherein the evaluation device (22) transmits a command, depending on the optimal trajectory, to at least one control unit (24) by which the curve is controlled. [6] Method according to claim 5, wherein several lanes are combined into one lane when calculating the optimal trajectory. [7] Method according to one of claims 5 or 6, wherein the optimal trajectory is determined taking into account other road users (26) who are on a preceding roadway (18). [8] Method according to any one of claims 5 to 7, wherein the optimal trajectory is determined taking into account local legislation. [9] Method according to any one of claims 1 to 8, wherein a turn signal of the autonomous vehicle (10) is activated when crossing a lane. [10] Autonomous vehicle (10) with at least one evaluation unit (22) and with at least one control unit (24), wherein the evaluation unit (22) is configured and designed to perform a method according to any one of claims 1 to 9.

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